Although the models are not provided, I was able to find them and the beakers with solid present in them are:
1C
2A
2C
3A
3C
This is determined by the fact that the beakers all have a piece of closely packed substance laying at the bottom. This closely packed lattice is characteristic of solid substances, and the fact that they exist in the solution in the solid states indicates that they are insoluble.
Answer:

Explanation:
To find the weight (W) of the pond contents first we need to use the following equation:
(1)
Where m the mass and g is the gravity
Also, we have that the mass is:
(2)
Where ρ is the density and V the volume
We cand calculate the volume as follows:
(3)
Where L is the length, w is the wide and d is the depth
By entering equation (2) and (3) into (1) we have:

Therefore, the weight of the pond is 6.65x10⁶ lbf.
I hope it helps you!
X is the answer that we do not know yet!!:)
The answer is 'equal'. Hydroxide ions are OH- and Hydrogen ions are H+. Have you noticed they're opposite charges? Positive + negative = neutral. That's all there is to it :)
Answer: Nuclear energy is by far the safest energy source in this comparison – it results in more than 442 times fewer deaths than the 'dirtiest' forms of coal; 330 times fewer than coal; 250 times less than oil; and 38 times fewer than gas.